I normally bake my pizzas on a smallish Weber gas grill and a glazed pizza stone, but the big problem that I always have is the bottom of the crust burns before the top cooks.
I've noticed that Modernist Cuisine (I don't have the book) recommends preheating a baking steel with a broiler then cooking the pizza with the broiler. That way it gets intense heat from the top and bottom.
I was thinking I could achieve the same thing by heating the bottom of the pizza with the gas and heating the top by putting some hot coals on a metal sheet a few inches above the stone. Maybe this would help the pizza cook in just a few minutes while having the top and bottom of the pizza cook at the same speed.
Usually when I cook with the gas grill, the temperature at the top of the grill (the built in thermometer) reads ~600°F and the temperature at the pizza stone level is well over 700°F (maxed out my over thermometer). When I cook the pizzas in my regular oven at 550°F, the crust doesn't cook enough and the cheese gets over melted and burns. In the oven, the pizzas also take forever to cook; probably over 10 minutes. I would like to cook them in <5min.
I'm wondering if anyone has heard of using coals above the pizza in a gas grill to heat more evenly. I did some searches and couldn't find anyone doing this specifically. I think the idea should be essentially the same as putting a baking steel above the pizza, which many people do, but without dishing out $100.